can someone let me know how likely it is that i'm pregnant??

over the weekend my boyfriend and i had sex without a condom, he pulled out but it was our second round so i think there could've still been sperm left on his penis when he went back in. i'm on the pill but i was supposed to be on the placebo pills, but i took the next active pill in the pack and forgot the next day, the day we had sex. today i've been exhausted and my back has been hurting. i've also had weird creamy almost chunky discharge.